1. Field of the Invention
The present invention pertains to an electronic device and particularly relates to an electronic device that transmits information (data) to and receives information (data) from a partner device by laser light that has been modulated in accordance with transmission information (data).
2. Description of the Related Art
Recently, there has been proposed a technology that realizes wireless communication at an extremely high transmission speed (e.g., 1 Gb/s) using laser light in the wavelength region of infrared (e.g., see KDDI R&D Laboratories, “The Realization of Infrared Wireless Communication at a Transmission Speed of 1 Gbit/s Using a Mobile Telephone”, online, searched Jan. 21, 2008, Internet, URL: http://www.kddilabs.jp/press/img/83—1.pdf). By using this technology, it becomes possible, in the transmission and reception of data between arbitrary electronic devices, to complete, when at least one of the electronic devices is portable and transmits and receives large quantities of data, the transmission and reception of large quantities of data in a short amount of time without having to interconnect, via a communication cable or the like, the electronic devices that transmit and receive data. For that reason, application of this technology to various purposes is expected, such as being able to realize a considerable reduction in communication time in wireless communication between existing devices and being able to realize, by wireless communication, the transmission and reception of large quantities of data between devices for which the transmission and reception of data by wireless communication had not conventionally been assumed.
For example, in Japanese Patent No. 3,494,683, there is disclosed a portable radiographic image converter (also called an “electronic cassette” below). This electronic cassette has a built-in radiation detector and a built-in image memory and is configured to store, in the image memory as image data, a radiographic image that is detected by the radiation detector, convert the image data read from the image memory into wireless signals, and output the wireless signals to an external signal processing circuit. In medical sites, there are numerous devices for which installation in an environment where radio waves are radiated is not desirable. Therefore, the wireless communication format suited for the above-described electronic cassette has conventionally been limited to infrared communication or the like that complies with the standards of the Infrared Data Association (IrDA). However, whereas communication speed is about 115 kb/s to 6 Mb/s in infrared communication that complies with the standards of the IrDA, in this type of medical device that handles radiographic images, lossless compression, where the compression rate is low when compressing image data, is selected in order to avoid radiogram interpretation from being adversely affected, so an extremely long time is required to transfer image data. For this reason, when the aforementioned communication by laser light is applied as the wireless communication format in the electronic cassette, a considerable reduction in the image data transfer time can be realized.
Relating to the above, as a technology that improves safety in a device that handles laser light, in Japanese Patent Application Laid-Open (JP-A) No. 2007-81134, there is disclosed an optical communication module of a configuration equipped with a laser diode disposed in a lead frame and a transparent resin component that serves as an adjustment component that performs laser diode light output distribution expansion and output adjustment. In this optical communication module, the transparent resin component is configured to include a transparent resin that seals the laser diode and a glass filler that is added to this transparent resin, is distributed substantially uniformly throughout all of the transparent resin and exhibits a light transmission and diffusion function.
In an aspect where electronic devices perform wireless communication using laser light, when at least one of the electronic devices is portable, wireless communication is performed in a state where both of the electronic devices are disposed in a positional relationship where wireless communication by laser light is possible. At this time, since at least one of the electronic devices is portable, when pressing force or vibration acts on the casing of the electronic device in the middle of communication by laser light, the relative positions of both of the electronic devices may change. In accompaniment with this change in the relative positions, there has been the potential for the laser light to leak out from the intervening space between both of the electronic devices.
Particularly when non-visible laser light is used in wireless communication, a user cannot see the laser light, and therefore, even if the laser light are leaking out, the user cannot recognize that the laser light is leaking out.
With respect thereto, the technology described in JP-A No. 2007-81134 is a technology that realizes an expansion of the light output distribution of the optical communication module and a drop in the light output amount of the optical communication module as a result of the light from the laser diode being repeatedly refracted by the glass filler. Consequently, the technology does not contribute in any way to preventing leakage of the laser light when the relative positions of the electronic devices during communication by laser light have changed.